Fatal invasive trichosporonosis due toTrichosporon loubieriin a patient with T-lymphoblastic lymphoma

Vancomycin enhances growth and virulence of Trichosporon spp. planktonic cells and biofilms

Invasive fungal infections (IFIs) are important worldwide health problem, affecting the growing population of immunocompromised patients. Although the majority of IFIs are caused by Candida spp., other fungal species have been increasingly recognized as relevant opportunistic pathogens. Trichosporon spp. are members of skin and gut human microbiota. Since 1980's, invasive trichosporonosis has been considered a significant cause of fungemia in patients with hematological malignancies. As prolonged antibiotic therapy is an important risk factor for IFIs, the present study investigated if vancomycin enhances growth and virulence of Trichosporon. Vancomycin was tested against T. inkin (n = 6) and T. asahii (n = 6) clinical strains. Planktonic cells were evaluated for their metabolic activity and virulence against Caenorhabditis elegans. Biofilms were evaluated for metabolic activity, biomass production, amphotericin B tolerance, induction of persister cells, and ultrastructure. Vancomycin stimulated planktonic growth of Trichosporon spp., increased tolerance to AMB, and potentiates virulence against C. elegans. Vancomycin stimulated growth (metabolic activity and biomass) of Trichosporon spp. biofilms during all stages of development. The antibiotic increased the number of persister cells inside Trichosporon biofilms. These cells showed higher tolerance to AMB than persister cells from VAN-free biofilms. Microscopic analysis showed that VAN increased production of extracellular matrix and cells in T. inkin and T. asahii biofilms. These results suggest that antibiotic exposure may have a direct impact on the pathophysiology of opportunistic trichosporonosis in patients at risk.

LAY ABSTRACT

This study showed that the vancomycin stimulated Trichosporon growth, induced morphological and physiological changes on their biofilms, and also enhanced their in vivo virulence. Although speculative, the stimulatory effect of vancomycin on fungal cells should be considered in a clinical scenario.

First case of bloodstream infection of Trichosporon loubieri in a patient with B-cell lymphocytic leukemia in China

Trichosporon loubieri is an opportunistic pathogenic fungus that could causes invasive infections for human, which rarely been reported. In the present study, we reported a case of bloodstream infection from a patient with Ph-positive B-cell acute lymphocytic leukemia (B-ALL) due to Trichosporon loubieri. Trichosporon loubieri was identified by Internal Transcribed Spacer (ITS) gene sequencing. The patient was treated by intravenous voriconazole (VCZ) and amphotericin B (AmB) according to antifungal susceptibility testing and he was still alive so far. To the best of our knowledge, this is the fourth report of human bloodstream infection due to Trichosporon loubieri and the first survival case of its kind in an immunocompromised patient.

Complicated urinary tract infection by Trichosporon loubieri

We report two cases of complicated Urinary Tract Infection, one with nephrostomy tube left in-situ and other with bladder outlet obstruction, caused by Trichosporon loubieri. Both patients responded well to antifungal treatment along with change/removal of catheters. In both the cases, correct identification of T. loubieri was done by IGS1 sequencing. Prompt identification and timely management headed to good clinical outcome. Hence, clinicians should be aware of T. loubieri as an emerging fungi causing human infections.

Trichosporon loubieri Fungemia in a 39-Year-Old Caucasian Woman With B-Cell Lymphoblastic Leukemia

We report a case of Trichosporon loubieri (T. loubieri) fungemia with likely liver involvement in a 39-year-old Caucasian patient with relapsed B-cell acute lymphoblastic leukemia after an allogeneic hematopoietic cell transplant. This is the fifth published case of T. loubieri infection and only the third case of T. loubieri fungemia, to our knowledge. All 3 cases of T. loubieri infection with fungemia had liver involvement.

Invasive Trichosporon Infection: a Systematic Review on a Re-emerging Fungal Pathogen

Objectives: This review aimed to better depict the clinical features and address the issue of therapeutic management of Trichosporon deep-seated infections.

Methods: We comprehensively reviewed the cases of invasive Trichosporon infection reported in the literature from 1994 (date of taxonomic modification) to 2015. Data from antifungal susceptibility testing (AST) studies were also analyzed.

Results: Two hundred and three cases were retained and split into four groups: homeopathy (n = 79), other immunodeficiency conditions (n = 41), miscellaneous (n = 58) and newborns (n = 25). Trichosporon asahii was the main causative species (46.7%) and may exhibit cross-resistance to different antifungal classes. The unfavorable outcome rate was at 44.3%. By multivariate analysis, breakthrough infection (OR 2.45) was associated with unfavorable outcome, whilst the use of an azole-based therapy improved the prognosis (OR 0.16). Voriconazole-based treatment was associated with favorable outcome in hematological patients (73.6 vs. 41.8%; p = 0.016). Compiled data from AST demonstrated that (i) T. asahii exhibits the highest MICs to amphotericin B and (ii) voriconazole has the best in vitro efficacy against clinical isolates of Trichosporon spp.

Conclusions:Trichosporon infection is not only restricted to hematological patients. Analysis of compiled data from AST and clinical outcome support the use of voriconazole as first line therapy.

Epidemiology and Outcome of Trichosporon Fungemia: A Review of 185 Reported Cases From 1975 to 2014

We first reviewed the English-language literature for reported cases of Trichosporon fungemia over the past four decades, and did comprehensive analysis in order to guide our understanding of epidemiology and outcome-related aspects, especially the antifungal treatment and CVC management.

Background. Trichosporon species have emerged as an important non-Candida spp yeast pathogen in immunocompromised patients in recent decades; however, the systemic analysis of Trichosporon epidemiology has seldom been reported.

Methods. We reviewed 185 reported cases of Trichosporon fungemia from 1975 to 2014 in the English-language literature, and the epidemiology and prognostic factors of the included cases are described.

Results. The number of cases reported has increased with time, especially over the past decade. During the 3 decades from 1975 to 2004, the most commonly used antifungal compounds were amphotericin B/liposomal amphotericin B; however, in recent decades (2005–2014), triazoles (especially voriconazole) have become the most widely used agents, significantly improving outcome in the reported cases. Correlation analysis revealed that negative outcome is associated with several prognostic factors, including a history of antimicrobial use, bacterial bloodstream coinfection, prophylactic/empirical antifungal therapy, Trichosporon beigelii infection, and receiving the antifungal regimen of amphotericin B/liposomal amphotericin B. In addition, a significantly greater proportion of patients with a positive outcome had fungemia without invasive tissue infection and received a voriconazole regimen or an AmB-triazole combined regimen. Significant positive outcome was also associated with patients who had recovered from neutropenia or after central venous catheter removal.

Conclusions. Voriconazole can be recommended as a first-line antifungal compound to treat Trichosporon fungemia; the immune status of the host plays a crucial role in the outcome of this infection, and the removal of vascular catheters should be considered if feasible.

The first isolation of Trichosporon coremiiforme from soil in Iran

Background and Purpose:

Trichosporon is a genus of anamorphic basidiomycetous yeast which is widely distributed in nature and is found in tropical and temperate areas. The aim of this work was to study the isolation, identification and molecular analysis of Trichosporon species in soil.

Materials and Methods:

In order to isolate and identify Trichosporon species in soil, 30 samples were collected from 30 different locations across Iran. The isolates were identified by means of the standard methods of yeast identification. To confirm morphological identification, genomic DNA was extracted and the hypervariable D1/D2 domain of the large-subunit (LSU) ribosomal DNA (rDNA) gene was amplified by polymerase chain reaction (PCR), using primer pair NL-1/NL-4, and then the sequences were analyzed.

Results:

According to the morphological and physiological assessments, isolates were identified as T. coremiiforme. The isolates formed chlamydospore after one week on yeast-malt (YM) agar medium. Using Blast program, we found that the D1/D2 sequences of the T. coremiiforme isolates from Iran (accession no: KP055040 and KP055041) showed 99% homology with the T. coremiiforme deposited in GenBank. All the T. coremiiforme isolates placed in the Ovoides cluster were well-supported by bootstrap values.

Conclusion:

The present study is the first attempt to survey Trichosporon in soil of Iran. To the best of our knowledge, this is the first investigation of T. coremiiforme in Iran.

Non-healing ulcer due to Trichosporon loubieri in an immunocompetent host and review of published reports

We report here a case of non-healing ulcer due to Trichosporon loubieri in an apparently immunocompetent female. The identity of isolate was confirmed by DNA sequencing of D1/D2 region of 26S rDNA. The minimum inhibitory concentrations of the isolate were amphotericin B-0.5 μg/ml; fluconazole-4 μg/ml; posaconazole-0.25 μg/ml; voriconazole-0.06 μg/ml. The patient was managed by extensive debridement and oral fluconazole 150 mg daily for 6 weeks. She responded to therapy. To the best of our knowledge, till date, this is the fourth report of human infection due to T. loubieri and the first of its kind in an immunocompetent host. A review of published literature on infections due to T. loubieri is also included.

Diagnostic accuracy of histopathologic and cytopathologic examination of Aspergillus species

To assess the diagnostic accuracy of histopatho-logic and cytopathologic examination (HCE) of Aspergillus species (spp), we performed an 11-year retrospective review to correlate surgical/cytology cases with a diagnosis of Aspergillus spp with their concurrent fungal culture results. Diagnostic accuracy was defined as the percentage of cases with culture-proven Aspergillus spp divided by the number of cases diagnosed as Aspergillus spp on HCE that had growth on fungal culture. Ninety surgical/cytology cases with concurrent fungal culture were reviewed, 58 of which grew a fungal organism. Of these 58 cases, 45 grew an Aspergillus spp, whereas 13 grew an organism other than Aspergillus spp, including both common (Scedosporium, Fusarium, and Paecilomyces spp) and uncommon mimickers (Trichosporon loubieri), resulting in a diagnostic accuracy of 78%. The low diagnostic accuracy indicates that several fungal organisms can morphologically mimic Aspergillus spp and can only be distinguished by fungal culture and DNA sequencing.

A case report of tinea pedis caused by Trichosporon faecale in Iran

Trichosporon species are known as the causative agents of cutaneous infections and are involved in systemic, localized, as well as disseminated mycoses particularly in immunocompromised patients. Here we report a case of tinea pedis infection caused by Trichosporon faecale in a healthy 29-year-old woman in the north of Iran. Macroscopic and microscopic characteristics using direct examination as well as culture method revealed the causative agent as Trichosporon species. Molecular analysis of the internal transcribed spacer region validated the initial result and indicated that this case of tinea pedis was caused by T. faecale. The patient was recovered after treatment with topical myconazole accompanied with oral fluconazole.

Lindnera (Pichia) fabianii blood infection after mesenteric ischemia

Lindnera (Pichia) fabianii (teleomorph of Candida fabianii) is a yeast species rarely involved in human infections. This report describes the first known human case of a Lindnera fabianii blood infection after mesenteric ischemia. The 53-year-old patient was hospitalized in the intensive care unit after a suicide attempt and was suffering from a mesenteric ischemia and acute renal failure. Lindnera fabianii was recovered from an oropharyngeal swab, then isolated from stool and urine samples before the diagnosis of the blood infection. Caspofungin intravenous treatment was associated with a successful outcome. Final unequivocal identification of the strain was done by sequencing the internal transcribed spacer (ITS) region, and regions of 18S rDNA gene and of the translation elongation factor-1α gene. Until our work, the genomic databases did not contain the complete ITS region of L. fabianii as a single nucleotide sequence (encompassing ITS1, the 5.8S rDNA and ITS2), and misidentification with other yeast species, e.g., Lindnera (Pichia) mississippiensis, could have occurred. Our work demonstrates that the usual DNA barcoding method based on sequencing of the ITS region may fail to provide the correct identification of some taxa, and that partial sequencing of the EF1α gene may be much more effective for the accurate delineation and molecular identification of new emerging opportunistic yeast pathogens.